Lure a girl in a way that could be irregular (9)
I believe the answer is:
guerrilla
'irregular' is the definition.
(synonyms)
'lure a girl in a way' is the wordplay.
'in a way' is an anagram indicator.
'lure'+'a'+'girl'='lureagirl'
'lureagirl' anagrammed gives 'GUERRILLA'.
'that could be' acts as a link.
(Other definitions for guerrilla that I've seen before include "Resistance fighter" , "One fighting" , "Underground fighter" , "Member of an irregular armed force" , "freedom fighter?" .)